This script creates a new OPSI package structure for various types of
installer methods (Batch, Inno, NSIS...) to make software packaging a little easier.

The script needs the "convert" command from the ImageMagick software suite and
cURL for downloading the setup file and package logo.

```
Usage:
  ./new-package.sh <product-id>

Optional parameters:
  -d <Product Description>      Adds a description to the package
  -n <Product Name>             Adds a product name instead of autogenerating one
  -g yes                        Adds the Gruelag prefix to package ID and name
  -u <Program URL>              Downloads an installer file from the specified URL
  -i <Logo URL>                 Applies a logo to the package from the specified URL
  -v <Program version>          Sets the version of the program (not the package)
  -t <Package Type>             Sets the type of package to create, see below:

Package types:
  winbatch                      Creates a blank WinBatch package
  winbatch-inno                 Creates a blank INNO Installer WinBatch package
  winbatch-nsis                 Creates a blank NSIS Installer WinBatch package
  dosicon                       Creates a blank DosInAnIcon package
  execps                        Creates a blank ExecWith Powershell package
  zip                           Creates a blank ZIP based package
  msi                           Creates a blank MSI installer package

Optional parameters for "zip" type package:
  -e <filename.exe>     Specifies the launcher executable inside the ZIP file
```